Mutant Spiders rule the planet Metebelis Three in the far future, holding
a regressive Earth colony in a grip of fear. The leader of the Spiders,
the mammoth Great One, is constructing a device using Metebelis' powerful
blue crystals which will increase her mental powers a millionfold. But the
Doctor is in possession of the last crystal, and soon he and Sarah find
themselves pursued by the Spiders and their human agents.

Production

Roger Delgado had played the Master on Doctor Who since 1971, but
during 1972 and 1973 made only occasional appearances in the programme.
Despite this, he was discovering that many casting directors believed that
he was still fully committed to Doctor Who, and were passing him
over for work. As such, during the making of Frontier In Space -- Delgado's only story in
Season Ten -- he and producer Barry Letts came to an agreement that the
Master would be written out of Doctor Who in the final serial of
the eleventh season.

To author the Master's swansong, the producer turned to Robert Sloman, who
had written (with considerable input from Letts) the concluding stories of
each of the last three seasons, most recently The
Green Death. Sloman was beginning to tire of Doctor Who but
acquiesced, and on February 15th, 1973 accepted a commission for a
storyline entitled “The Final Game”. Drawing on Letts'
proclivity for Eastern philosophy and the feature film Forbidden
Planet, “The Final Game” would have
revealed the Doctor and the Master to be two facets of the same person,
with the Master as the “id” (instinctual needs and desires)
and the Doctor as the “ego” (conscious perception of and
adaptation to reality). At the adventure's climax, the Master would have
perished in an explosion, in the process saving the Doctor and others from
death -- although it would have remained ambiguous as to whether or not
this was an act of redemption.

It was decided to draw on Eastern concepts with a story in
which the Doctor confronts his destructive thirst for knowledge

Unfortunately, “The Final Game” had to be abandoned in the
wake of the events of June 18th, when Delgado died in a car accident in
Turkey. This precipitated the final dissolution of the team which had
carried Doctor Who through the Seventies, as it appeared that
Letts, script editor Terrance Dicks, and star Jon Pertwee would all leave
Doctor Who following Season Eleven. A reluctant Sloman was
therefore asked to deliver a new storyline under his original commission,
which would bring the era of the Third Doctor to a close.

Working with Letts, it was decided to again draw on Eastern notions by
developing a story in which the Doctor confronts his destructive and
rapacious thirst for knowledge. Letts also wanted to reward Pertwee -- who
loved gadgets and vehicles of all kinds -- with an extended chase scene
(which would end up forming the bulk of episode two). This was also an
opportunity to wrap up the Metebelis Three subplot which had lightly run
through Season Ten. Originally called “The Planet Of The
Spiders”, the title was shortened to simply Planet Of The
Spiders by the time the scripts were commissioned on December 5th.
This was Sloman's last television credit; although the writer submitted
one further storyline the following November, it was not accepted and
Sloman thereafter confined himself to work in the newspaper industry.

Letts' agreement with the BBC permitted him to direct one story every
recording block if he so chose; he had last helmed Carnival Of Monsters, and now opted to direct
Planet Of The Spiders. Work began on Serial ZZZ with an
experimental effects day at BBC Television Centre on February 22nd, 1974
before moving out on location for five days between March 11th and
15th.

The 11th was spent at three locations in Berkshire: Tidmarsh Manor at
Tidmarsh was K'anpo's monastery, Mortimer Railway Station at Stratfield
Mortimer was the train station, and rural road scenes were completed on
nearby Bloomfieldhatch Lane. The remainder of the filming schedule was for
scenes comprising part two's lengthy chase sequence. March 12th took cast
and crew to Membury Airfield in Membury, Wiltshire. More material was
filmed there on the 13th, as well as at Le Marchant Barracks in Devizes,
Wiltshire. Finally, the 14th and 15th saw a relocation to the River Severn
near Westbury, Gloucestershire.

April 2nd marked Tom Baker's first day on the Doctor Who set

Planet Of The Spiders followed the usual Doctor Who studio
recording pattern of taping in fortnightly two-day blocks, this time on
Tuesdays and Wednesdays. The first session occurred on April 2nd and 3rd
in BBC Television Centre Studio 1, and covered all the material from parts
one and two. Also completed on the Tuesday were the scenes set in the
Doctor's lab from episodes three and six; this included the regeneration
scene, and marked Tom Baker's first day on set. Nicholas Courtney
ad-libbed the Brigadier's closing line, “Well, here we go
again.”

The second block, on April 16th and 17th in TC8, was devoted solely to
Earthbound sequences from the final four installments. Kismet Delgado --
Roger Delgado's widow -- joined the cast at this stage, as one of the
Spider voice artistes. These days brought Richard Franklin's time on
Doctor Who to an end. Franklin's subsequent work was mainly in the
theatre, although he did return to play Mike Yates in both The Five Doctors and Dimensions In Time. Franklin also wrote the
comedic stage play Recall UNIT: The Great Tea Bag Mystery, and
penned a novel about Yates entitled The Killing Stone which did not
see publication.

Recording on Planet Of The Spiders concluded on April 30th and May
1st in TC6, involving all the Metebelis Three scenes. Although this
completed Season Eleven, the production block would continue with Tom
Baker's first story, Robot. Unfortunately,
Letts faced several difficulties in editing. First, the original cut of
episode three was too short, and so material was inserted which had
originally been intended for part four. This and other cuts created a
domino effect, with Letts having to pull material back from episodes five
and six. In addition to reprising the episode five cliffhanger several
minutes into the final installment, the situation also forced Letts to
include the Cave of Crystal flashback in episode six in order to ensure it
had a sufficient running time.

Terrance Dicks became the primary contributor to Target
Books' range of Doctor Who novelisations

Part six of Planet Of The Spiders aired on June 8th, bringing to a
close far more than just Season Eleven. It was also Terrance Dicks' final
credit as script editor. Dicks thereafter returned to freelance writing,
although he also produced some classics serials in the mid-Eighties. Dicks
maintained a very close connection with Doctor Who, providing
several scripts for the programme. Additionally, Dicks became the primary
contributor to Target Books' range of Doctor Who novelisations.
Following the cessation of that line, he continued to scribe original
Doctor Who novels for both Virgin Publishing and BBC Books,
including Timewyrm: Exodus, Blood Harvest, The Eight
Doctors and Deadly Reunion (cowritten with Letts). Dicks also
wrote the stage play Doctor Who: The Ultimate Adventure, and was a
candidate to script what would eventually become the TV movie Doctor Who (1996).

Most significantly, however, Planet Of The Spiders brought Jon
Pertwee's successful five-year stint as the Doctor to its culmination.
Pertwee continued to make appearances in film, on stage and on radio,
including regular roles as the host of the game show Whodunnit? and
as the title character in the children's programme Worzel Gummidge.
His involvement with Doctor Who never flagged, as Pertwee became a
fixture on the convention scene in the Eighties and early Nineties. He
also returned to the programme on multiple occasions: in the televised
anniversary specials The Five Doctors and Dimensions In Time, the stage show Doctor
Who: The Ultimate Adventure, and the radio plays The Paradise Of
Death and The Ghosts Of N-Space. Recordings of Pertwee were
even used posthumously in the Big Finish Productions audio adventure
Zagreus. Sadly, Jon Pertwee died of a heart attack on May 20th,
1996.

Sources

Doctor Who: The Handbook: The Third Doctor by David J Howe and
Stephen James Walker (1996), Virgin Publishing, ISBN 0 426 20486 7.